.TH "QwtPlotHistogram" 3 "Fri Apr 15 2011" "Version 6.0.0" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtPlotHistogram \- 
.PP
\fBQwtPlotHistogram\fP represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ ).  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_plot_histogram.h>\fP
.PP
Inherits \fBQwtPlotSeriesItem< QwtIntervalSample >\fP.
.SS "Public Types"

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.RI "enum \fBHistogramStyle\fP { \fBOutline\fP, \fBColumns\fP, \fBLines\fP, \fBUserStyle\fP =  100 }"
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.SS "Public Member Functions"

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.RI "\fBQwtPlotHistogram\fP (const QString &title=QString::null)"
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.RI "\fBQwtPlotHistogram\fP (const \fBQwtText\fP &title)"
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.RI "virtual \fB~QwtPlotHistogram\fP ()"
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.RI "virtual int \fBrtti\fP () const "
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.RI "void \fBsetPen\fP (const QPen &)"
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.RI "const QPen & \fBpen\fP () const "
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.RI "void \fBsetBrush\fP (const QBrush &)"
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.RI "const QBrush & \fBbrush\fP () const "
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.RI "void \fBsetSamples\fP (const QVector< \fBQwtIntervalSample\fP > &)"
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.RI "void \fBsetBaseline\fP (double reference)"
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.RI "double \fBbaseline\fP () const "
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.RI "void \fBsetStyle\fP (\fBHistogramStyle\fP style)"
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.RI "\fBHistogramStyle\fP \fBstyle\fP () const "
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.RI "void \fBsetSymbol\fP (const \fBQwtColumnSymbol\fP *)"
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.RI "const \fBQwtColumnSymbol\fP * \fBsymbol\fP () const "
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.RI "virtual void \fBdrawSeries\fP (QPainter *p, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, const QRectF &canvasRect, int from, int to) const "
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.RI "virtual QRectF \fBboundingRect\fP () const "
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.RI "virtual void \fBdrawLegendIdentifier\fP (QPainter *, const QRectF &) const "
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.SS "Protected Member Functions"

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.RI "virtual \fBQwtColumnRect\fP \fBcolumnRect\fP (const \fBQwtIntervalSample\fP &, const \fBQwtScaleMap\fP &, const \fBQwtScaleMap\fP &) const "
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.RI "virtual void \fBdrawColumn\fP (QPainter *, const \fBQwtColumnRect\fP &, const \fBQwtIntervalSample\fP &) const "
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.RI "void \fBdrawColumns\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const "
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.RI "void \fBdrawOutline\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const "
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.RI "void \fBdrawLines\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const "
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.SH "Detailed Description"
.PP 
\fBQwtPlotHistogram\fP represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ ). 

The representation depends on the \fBstyle()\fP and an optional \fBsymbol()\fP that is displayed for each interval.
.PP
\fBNote:\fP
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The term 'histogram' is used in a different way in the areas of digital image processing and statistics. Wikipedia introduces the terms 'image histogram' and 'color histogram' to avoid confusions. While 'image histograms' can be displayed by a \fBQwtPlotCurve\fP there is no applicable plot item for a 'color histogram' yet. 
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.SH "Member Enumeration Documentation"
.PP 
.SS "enum \fBQwtPlotHistogram::HistogramStyle\fP"Histogram styles. The default style is \fBQwtPlotHistogram::Columns\fP.
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP, \fBsetSymbol()\fP, \fBsymbol()\fP, \fBsetBaseline()\fP 
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.PP
\fBEnumerator: \fP
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.TP
\fB\fIOutline \fP\fP
Draw an outline around the area, that is build by all intervals using the \fBpen()\fP and fill it with the \fBbrush()\fP. The outline style requires, that the intervals are in increasing order and not overlapping. 
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\fB\fIColumns \fP\fP
Draw a column for each interval. When a \fBsymbol()\fP has been set the symbol is used otherwise the column is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP. 
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\fB\fILines \fP\fP
Draw a simple line using the \fBpen()\fP for each interval. 
.TP
\fB\fIUserStyle \fP\fP
Styles >= UserStyle are reserved for derived classes that overload \fBdrawSeries()\fP with additional application specific ways to display a histogram. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "QwtPlotHistogram::QwtPlotHistogram (const QString &title = \fCQString::null\fP)\fC [explicit]\fP"Constructor 
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\fBParameters:\fP
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\fItitle\fP Title of the histogram. 
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.SS "QwtPlotHistogram::QwtPlotHistogram (const \fBQwtText\fP &title)\fC [explicit]\fP"Constructor 
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\fBParameters:\fP
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\fItitle\fP Title of the histogram. 
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.SS "QwtPlotHistogram::~QwtPlotHistogram ()\fC [virtual]\fP"
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Destructor. 
.SH "Member Function Documentation"
.PP 
.SS "double QwtPlotHistogram::baseline () const"\fBReturns:\fP
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Value of the baseline 
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\fBSee also:\fP
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\fBsetBaseline()\fP 
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.SS "QRectF QwtPlotHistogram::boundingRect () const\fC [virtual]\fP"\fBReturns:\fP
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Bounding rectangle of all samples. For an empty series the rectangle is invalid. 
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.PP
Reimplemented from \fBQwtPlotSeriesItem< QwtIntervalSample >\fP.
.SS "const QBrush & QwtPlotHistogram::brush () const"\fBReturns:\fP
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Brush used in a \fBstyle()\fP depending way. 
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\fBSee also:\fP
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\fBsetPen()\fP, \fBbrush()\fP 
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.SS "\fBQwtColumnRect\fP QwtPlotHistogram::columnRect (const \fBQwtIntervalSample\fP &sample, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap) const\fC [protected, virtual]\fP"Calculate the area that is covered by a sample
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\fBParameters:\fP
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\fIsample\fP Sample 
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\fIxMap\fP Maps x-values into pixel coordinates. 
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\fIyMap\fP Maps y-values into pixel coordinates.
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\fBReturns:\fP
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Rectangle, that is covered by a sample 
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.SS "void QwtPlotHistogram::drawColumn (QPainter *painter, const \fBQwtColumnRect\fP &rect, const \fBQwtIntervalSample\fP &sample) const\fC [protected, virtual]\fP"Draw a column for a sample in Columns \fBstyle()\fP.
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When a \fBsymbol()\fP has been set the symbol is used otherwise the column is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP.
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIrect\fP Rectangle where to paint the column in paint device coordinates 
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\fIsample\fP Sample to be displayed
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\fBNote:\fP
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In applications, where different intervals need to be displayed in a different way ( f.e different colors or even using differnt symbols) it is recommended to overload \fBdrawColumn()\fP. 
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.SS "void QwtPlotHistogram::drawColumns (QPainter *painter, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, intfrom, intto) const\fC [protected]\fP"Draw a histogram in Columns \fBstyle()\fP
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates. 
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\fIyMap\fP Maps y-values into pixel coordinates. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP, \fBsetSymbol()\fP, \fBdrawColumn()\fP 
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.SS "void QwtPlotHistogram::drawLegendIdentifier (QPainter *painter, const QRectF &rect) const\fC [virtual]\fP"Draw a plain rectangle without pen using the \fBbrush()\fP as identifier
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIrect\fP Bounding rectangle for the identifier 
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.PP
Reimplemented from \fBQwtLegendItemManager\fP.
.SS "void QwtPlotHistogram::drawLines (QPainter *painter, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, intfrom, intto) const\fC [protected]\fP"Draw a histogram in Lines \fBstyle()\fP
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates. 
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\fIyMap\fP Maps y-values into pixel coordinates. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.
.RE
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP, \fBsetPen()\fP 
.RE
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.SS "void QwtPlotHistogram::drawOutline (QPainter *painter, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, intfrom, intto) const\fC [protected]\fP"Draw a histogram in Outline \fBstyle()\fP
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates. 
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\fIyMap\fP Maps y-values into pixel coordinates. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted. If to < 0 the histogram will be painted to its last point.
.RE
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP 
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\fBWarning:\fP
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The outline style requires, that the intervals are in increasing order and not overlapping. 
.RE
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.SS "void QwtPlotHistogram::drawSeries (QPainter *painter, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, const QRectF &canvasRect, intfrom, intto) const\fC [virtual]\fP"Draw a subset of the histogram samples
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\fBParameters:\fP
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\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates. 
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\fIyMap\fP Maps y-values into pixel coordinates. 
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\fIcanvasRect\fP Contents rect of the canvas 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted. If to < 0 the series will be painted to its last sample.
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\fBSee also:\fP
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\fBdrawOutline()\fP, \fBdrawLines()\fP, \fBdrawColumns\fP 
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.PP
Implements \fBQwtPlotAbstractSeriesItem\fP.
.SS "const QPen & QwtPlotHistogram::pen () const"\fBReturns:\fP
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Pen used in a \fBstyle()\fP depending way. 
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\fBSee also:\fP
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\fBsetPen()\fP, \fBbrush()\fP 
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.SS "int QwtPlotHistogram::rtti () const\fC [virtual]\fP"\fBReturns:\fP
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QwtPlotItem::Rtti_PlotHistogram 
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.PP
Reimplemented from \fBQwtPlotItem\fP.
.SS "void QwtPlotHistogram::setBaseline (doublevalue)"
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Set the value of the baseline. Each column representing an \fBQwtIntervalSample\fP is defined by its interval and the interval between baseline and the value of the sample.
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The default value of the baseline is 0.0.
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\fBParameters:\fP
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\fIvalue\fP Value of the baseline 
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\fBSee also:\fP
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\fBbaseline()\fP 
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.SS "void QwtPlotHistogram::setBrush (const QBrush &brush)"Assign a brush, that is used in a \fBstyle()\fP depending way.
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\fBParameters:\fP
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\fIbrush\fP New brush 
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\fBSee also:\fP
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\fBpen()\fP, \fBbrush()\fP 
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.SS "void QwtPlotHistogram::setPen (const QPen &pen)"Assign a pen, that is used in a \fBstyle()\fP depending way.
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\fBParameters:\fP
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\fIpen\fP New pen 
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\fBSee also:\fP
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\fBpen()\fP, \fBbrush()\fP 
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.SS "void QwtPlotHistogram::setSamples (const QVector< \fBQwtIntervalSample\fP > &samples)"Initialize data with an array of samples. 
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\fBParameters:\fP
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\fIsamples\fP Vector of points 
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.SS "void QwtPlotHistogram::setStyle (\fBHistogramStyle\fPstyle)"Set the histogram's drawing style
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\fBParameters:\fP
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\fIstyle\fP Histogram style 
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\fBSee also:\fP
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\fBHistogramStyle\fP, \fBstyle()\fP 
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.SS "void QwtPlotHistogram::setSymbol (const \fBQwtColumnSymbol\fP *symbol)"
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Assign a symbol. In Column style an optional symbol can be assigned, that is responsible for displaying the rectangle that is defined by the interval and the distance between \fBbaseline()\fP and value. When no symbol has been defined the area is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP.
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\fBSee also:\fP
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\fBstyle()\fP, \fBsymbol()\fP, \fBdrawColumn()\fP, \fBpen()\fP, \fBbrush()\fP
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.PP
\fBNote:\fP
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In applications, where different intervals need to be displayed in a different way ( f.e different colors or even using differnt symbols) it is recommended to overload \fBdrawColumn()\fP. 
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.SS "\fBQwtPlotHistogram::HistogramStyle\fP QwtPlotHistogram::style () const"Return the current style 
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\fBSee also:\fP
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\fBHistogramStyle\fP, \fBsetStyle()\fP 
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.SS "const \fBQwtColumnSymbol\fP * QwtPlotHistogram::symbol () const"\fBReturns:\fP
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Current symbol or NULL, when no symbol has been assigned 
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\fBSee also:\fP
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\fBsetSymbol()\fP 
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.SH "Author"
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